Recycled aggregate concrete from large-scale production to sustainable field application

Abstract

Concrete waste is the most prominent construction and demolition waste generated by the construction industry, which is mainly disposed to landfills. Recycling this waste in the form of recycled concrete aggregates (RCA) and substituting it for natural aggregates in the production of concrete could lead to environmental conservation. A growing body of literature in lab settings has already recognized the importance of utilizing RCA in the production of new concrete. However, intense utilization of RCA in the large-scale industrial production of new concrete (structural and non-structural) is not widely accepted by international standards due to its high porosity, a disparity of source concrete and lack of territorial field studies. In this paper, two full-scale field studies of the foundation system and municipal sidewalk constructed with recycled aggregate concrete (RAC) are presented. In addition to this, the long-term performance of RAC examined for 5 years in terms of in-place compressive strength is reported. Moreover, strength correlations developed specifically for RAC for the estimation of compressive strength based on rebound numbers are discussed. This study shows that RCA has significant potential of using as substitution of natural aggregate in the production of concrete of 25 and 32 MPa compressive strength. Furthermore, RAC shows a higher rate of compressive strength development after 28 days of curing and results in comparable long-term compressive strength to conventional concrete. By providing an insight into the sustainable application of RCA in the production of new concrete, the results of this study can serve as a basis for updating the current standards in Canada.